Signal apparatus for telephone-switchboards.



G. H. RYDER.

SIGNAL APPARATUS FOR TELEPHONE SWITGHBOAR DS. APPLICATION FILED MAY 17, 1905. Q

AAAA l Mza xuwwww PATENTED MAY 26, 1908.

UNITED STATES GEORGEH. RYDE n, or soM ERVILLE, MASSACHUSETTS.

SIGNAL APPARATUS FOR TELEPHONE-SWITCHBOARDS.

No. 888,748. Specification of Application filed May 17,

To all whom it may concern:

Be it known that I, GEORGE H. RYDER, a citizen of the United States, residing at Somerville, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Signal Apparatus for Telephone-Switchboards; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to signaling apparatus for telephone switch-boards, and particularly to that class of signaling appa ratus which comprise a line signal and a supervisory or cord signal at the central exchange controlled by a single line relay.

The object of the present invention is to provide an improved and simplified construction and arrangement of signals and circuits whereby absolute certainty in the operation of the signals is secured and fine adjustments of the resistance of the signals and of their circuits are rendered unnecessary.

The present invention is embodied in a construction and arrangement in which a line signal and a cord or supervisory signal are employed, the line signal being in circuit Letters Patent. I

1905. Serial No. 260,834.

Patented May 26, 1908.

tacts. This arrangement of jack and plug contacts is considered to constitute a feature of the invention which may be used in connection with any suitable arrangement of the circuits of the line and supervisory signals which places them both under the control of the contacts of the line relay. In the preferred form of the invention, however, the circuit of the supervisory signal is so arranged that when this circuit is closed and the line signal short circuited the supervisory signal is in parallel with the relay contacts as when the circuit of the supervisory signal is arranged in this manner the supervisory signal remains in its normal or inoperative condition so long as the relay contacts are closed and is energized to produce a positive indication as soon as the relay contacts are opened.

In addition to the features above referred to the present invention also consists in certain constructions and arrangements hereinafter described and claimed, the advantages of which will be obvious to those skilled in the art.

The present invention will be clearly understood from an inspection of the accompanying drawing, in which is illustrated with the contacts of the line relay and the supervisory signal being in a circuit adapted to be placed under the control of the relay contacts. I

A feature of the present invention contemplates the provision of means for short circuiting the line signal when the supervisory signal is placed under the control of the relay contacts so that the line signal is practically deprived of current and has no effect upon the current passing through the supervisory signal. This feature of the invention also contemplates an arrangement whereby the supervisory signal is short circuited or practically deprived of current after being placed under the control of the relay contacts and while the relay contacts remain closed.

In the specific embodiment of the invention hereinafter described, the terminals of the line signal are connected to jack contacts which are arranged to be bridged by a plug contact connected in circuit with the supervisory signal so that the insertion of a plug in the jack acts to short circuit the line signal and at the same time place the supervisory signal under the control of the relay condiagrammatically a signal apparatus embodying the same in its preferred form.

Referring to the drawing, A indicates a subscribers station which is connected to a central exchange B by a circuit illustrated in the drawing as composed of two line wires 1 and 2. C indicates another subscribers station which is connected in a similar manner to the central exchange. The instruments at the subscribers stations are constructed and arranged in any well known or suitable manner, the arrangement illustrated on the drawing being one that is often employed in common battery systems. In the arrangement illustrated, 3 indicates the telephone receiver, 4 the transmitter, 5 the induction coil, 6 the call bell and 7 the hook switch upon which the receiver is supported. The transmitter and the call bell are bridged across the line wires, the call bell being in series with a condenser indicated at 8. The hook-switch is arranged to move between contacts 9 and 10, and when in normal position closes the circuit of the call bell. When the receiver is removed. from the hook-switch the hook-switch engages the contact 9 and closes the circuit of the transmitter.

At the central exchange a line relay 11 is lay 11, so that the relay is energized.

each other and are connected respectively to included in the line wires 1 and 2, and a bat- E tery 12 is interpolated between the two coils of the relay. When the receiver is removed from the hook-switch at the subscribers station, the engagement of the hook-switch with the contact 9 closes a circuit, including the line wires, the battery 12 and the line re- The line relay contacts are indicated at 13 and 14, and one of these contacts is connected to one pole of the battery 15 and the other contact is connected to the other pole of the battery 15, a line signal lamp 16 and a resistance 17 being included in this latter connection. The line signal lamp 16 is thus controlled by the relay contacts, the lamp being lighted as soon as the relay is energized by removing the receiver from the hook-switch at the subscribers station.

The cord or supervisory signal is indicated at 18 as a lamp and is included in a circuit which leads from the pole of the battery 15 which is connected to the relay contact 13 to a contact 19. This contact as illustrated forms a part of the usual plug, which, in con nection with the usual spring jack, is utilized to connect the lilies of two subscribers, 20 and 21 indicating the plug contacts which engage the spring contacts 22 and 23 of the jack when the plug is inserted, 24 and 25 indi cating the cord circuits, 26 and 27 the two parts of the repeating coil, and 28 the battery inserted between the parts of the repeating coil. The construction and arrangement of the spring jacks, plug contacts, cord circuits, and battery may be the same as have heretofore been used in telephone systems, it being understood that suitable listening and ringing keys are provided in the usual manner.

The circuit of the supervisory signal lamp 18 is normally open at the contact 19. In order to place the supervisory signal lamp under the control of the line relay contacts, jack contacts 29 and 30 are provided which, when the plug is inserted in the jack, are arranged to be engaged by the contact 19. The contacts 29 and 30 are insulated from the terminals of the line signal lamp 16. The engagement of the contact 19' with the contacts 29 and 30, therefore, closes the circuit of the supervisory signal lamp 18 and simultaneously bridges the terminals of the line signal lamp, thereby short circuiting and eX' tinguishing this lamp. The circuit for the supervisory signal lamp leads from one pole of the battery 15 through the resistance 17, the contacts 30 and 19, and signal lamp 18, back to the other pole of the battery. While the relay contacts 13 .and 14 are closed, how ever, there is a connection from the contacts 19 and 29 to the other pole of the battery, so that the su ervisory signal lamp is in parallel with the re ay contacts. This connection is of low resistance and forms a short circuit for 1 the supervisory signal lamp so that aslong as the line relay contacts are closed the supervisory signal lamp does not glow. As soon as the line relay contacts open, however, this short circuit is broken and the lamp 18 is lighted. The supervisory signal lamp is thus controlled by the relay contacts and indicates to the central operator the condition of the subscribers line.

In order to provide for a busy test on a multiple switch-board, the tip strands of the plug are grounded as indicated at 31, and that pole of battery 15 which is connected to the contacts 29 and 30 is grounded as indicated at The contact 29 may form the ordinary test thimble of the ack, or both the contacts 29 and 30 may form this thimble. The busy test is made in the usual manner by touching the tip of the plug to the test thimble, or to that part of the thimble which is formed by the contact 29. If theline is busy the relay contacts 13 and 14 will be closed, and the contact 29 will be connected to the ungrounded or free pole of the battery 15. A current will accordingly pass from this pole of the battery through the relay contacts to the contact 29, and thence over the tip strand 24 of the plug to the ground at 31 and then back to the grounded pole of the battery. It the line is not busy the relay contacts 13 and 14 will be open and no current will pass over the tip strand 24. If the line is not busy, but a plug still nected with the line which is being tested, a current will pass from the battery 15, through the supervisory signal lamp 18 connected with the inserted plug, to the contact 19, and then to the contact 29 which is touched by the tip of a plug, and over the tip strand of this latter plug to the ground 31.

In the arrangement above described it will be seen that when the supervisory signal is placed under the control of the contacts of the line relay, the line signal lamp is short circuited and has no effect whatever upon the supervisory signal lamp. The line and supervisory signal lamps can therefore be of remains in a jack cong any desired resistance, as the proper opera- 7 tion of the signals depends in no way upon their relative resistance. Also, there is no necessity that the resistance of the circuits in which the line and supervisory signals are included should be proportioned with relation to each other. The current from the battery always passes through the resistance 17 and consequently the resistance of the short circuit for the supervisory signal may be so low as to practically deprive the supervisory signal of current without short circuiting the battery when the relay contacts are closed.

The operation of the signal apparatus illustrated in the drawing and. above described has been sufliciently indicated to be readily understood by those skilled in the art, and

further description thereof is considered unnecessary.

The nature and scope of the present invention having been indicated, and a preferred embodiment of the invention having been specifically described, what is claimed 1sz- 1. A signal apparatus for telephone switchboards, having, in combination, a line relay, a line signal in circuit with the contacts of the relay, a supervisory signal, and means for short circuiting the line signal and for placing the supervisory signal under the control of the same relay contacts.

2. A signal apparatus for telephone switchboards, having, in combination, a line relay, a line signal in series with the contacts of the relay, signal terminals, a plug contact arranged to close the jack contacts, and a supervisory signal in circuit with the plug contact and under the control of the relay contacts while the jack contacts are closed by the plug contact.

3. A signal apparatus for telephone switchboards, having, in combination, a line relay, a line signal and a source of current in series with the relay contacts, a supervisory signal and means for short circuiting the line signal and connecting the supervisory signal in parallel with the relay contacts.

4. A signal apparatus for telephone switchboards, having, in combination, a line relay, a source of current having its poles connected to the relay contacts, a line signal inter polated between one relay contact and one pole of the source of current, jack contacts connected with the terminals of the line signal in series with the relay contacts, a plug contact arranged to close the jack contacts when the plug is inserted in the jack, said plug contact being connected to the other jack contacts connected with the line pole of the source of current, and a supervisory signal interpolated between the plug contact and the last mentioned pole of the source of current and under the control of the relay contacts while the jack contacts are closed by the plug contact.

5. A signal apparatus for telephone switchboards, having, in combination, a line relay, a source of current having its poles connected to the relay contacts, a line signal inter olated between one relay contact and one pole of the source of current, a cord signal, one terminal of which is connected to the other pole of the source of current, and means for short circuiting the line signal and connecting the other terminal of the cord signal to the first mentioned pole of the source of current in parallel with the relay contacts.

6. A signal apparatus for telephone switchboards, having, in combination, a line relay, a line signal a source of current and a resistance in series with the relay contacts, a cord signal, means for short circuiting the line signal and connecting the cord signal in parallel with the relay contacts and in series with the resistance.

7. In a signal apparatus for telephone switch-boards, a line relay, a line signal a resistance and a source of current in series with the contacts of the relay, a cord circuit including a supervisory signal and a plug contact and means whereby the line signal is short circuited by the plug contact and the supervisory signal is placed under the control of the same relay contacts.

In testimony whereof I affiX my signature, in presence of two witnesses.

GEORGE H. RYDER.

Witnesses:

FRED O. FIsH, HORACE VAN EVEREN. 

